Project

Architectural Finish with Rented Gear

Contractor Kreuzer shows how it‘s done on Gilching Community Centre

The architects specified a superior fair-faced concrete finish. It was achieved with every pour using specially prepared rented MEVA Mammut 350 wall formwork.

A new community centre is being built in Gilching, a town near Munich in southern Germany. The complex is up to three levels high. Half the 2,000 m² walls required a top concrete finish.

The architect, enthusiastic after the trial pour, chose the Mammut 350 on account of its symmetrical tie-hole and joint pattern. Contractor Kreuzer requested MEVA to prepare the rented panels to achieve the exceptional finish required. The 3.50 m high walls were poured with the system’s large 2.50 by 3.50 m panels, making extensions unnecessary.

Preparing the rental formwork is a standard procedure for the MEVA logistics centres whenever unusually high requirements are placed on the concrete finish. But good preparation of the formwork alone is not the only guarantee for a top finish. Importantly, it is the way work is conducted that decides on the result. The Gilching site stuck to these simple rules and shows how it can be done.

Always start with a trial pourThe higher the demand on concrete finish, the more important is a trial pour. It allows the site to test the interaction between facing, concrete mixture, setting behaviour, climate, pouring and compacting. Sometimes even small changes such as using an alternative compacting technique can have an enormous effect on the result.

Ensure a stable formwork setupThis is important whenever abutments, wall sockets and offsets, frequent on this project, have to be mastered. If the panels are not tightly joined, high pour pressures can cause them to slide apart, allowing the fresh concrete to bleed. This leads to unsightly effects on the finished surface.

Avoid bleeding at joints, tie-holes and edgesTo achieve clean joints, edges and areas around tie-holes, it is advisable to proceed as follows:

Attach a sponge rubber tape around the side of one panel per joint. When the joint expands due to the concrete presssure, the sponge tape expands accordingly, preventing the concrete from leaking.

Using a sponge rubber tape on the cones prevents concrete from bleeding around the tie hole(see photo above right)

Clean-cut, sharp edges are achieved by using campher strips at wall ends.

Best practice when pouringPlace the concrete layer by layer. The concrete should not fall further than 1.50 m, because its components may segregate, leaving behind a surface with varying, unsightly grain patterns. This can only be avoided by taking care during every concrete pour.

Compact with utmost careIf compacting is not done properly, unsightly bubbles may stay behind on the surface. Another unwanted effect is that the concrete may be knocked off the rebar, leading to rust.

Which compacting method works best for which purpose is explained in our FormworkPress special edition XII/2013. E-mail us to receive your personal copy by post: infomanagement@meva.de.

Clean the panels after every pourUse either a high pressure washer or a rotation cleaner on the facing to clean the panels thoroughly after every pour, as was done on this site. Dirt and residues on the facing inevitably leave their mark on the finished surface. After cleaning, a thin haze of release agent is sprayed on each panel.

Repair damages to the facingNail holes or scratches on the all-plastic facing alkus can be repaired easily on site using the alkus repair set. This ensures a blemish-free facing and a perfect pour result throughout the job. The Gilching site proves how well this combination of careful and clean procedures works even when demands on concrete finish are very high.

“I’m enthusiastic about the specially prepared Mammut 350 panels“says project manager Marko Žugec, representing subcontractor Tehmont Gradnja, who did the concrete works. He was delighted about being able to clean and repair the facing on site. And the selection of different panel sizes made it easy to handle irregular wall layouts without any fuss.

MEVA STB 450 offers flexible solution for narrow, inclined rail section: Near the municipality of Gretzenbach, the four-track route branches into two separate lines. Here, the two southern tracks gradually descend and pass below the cantonal road before entering the new Eppenberg Tunnel.